Magnetic instabilities and resulting energy conversion in astrophysics

dc.contributor.advisorMilosavljević, Miloš
dc.creatorKagan, Daniel Rossen
dc.date.accessioned2014-09-16T16:03:14Zen
dc.date.issued2013-08en
dc.date.submittedAugust 2013en
dc.date.updated2014-09-16T16:03:14Zen
dc.descriptiontexten
dc.description.abstractBecause the universe is primarily composed of plasma, the interaction of plasmas and magnetic fields is of great importance for astrophysics. In this dissertation, we investigate three magnetic instabilities and examine their possible effects on astrophysical objects. First, we model solar coronal structures as Double Beltrami states, which are the lowest energy equilibria of Hall magnetohydrodynamics. We find that these states can undergo a catastrophe with characteristics similar to those of a solar eruption, such as a flare or coronal mass ejection. We then investigate magnetic reconnection and particle acceleration in moderately magnetized relativistic pair plasmas with three-dimensional particle-in-cell simulations of a kinetic-scale current sheet. We find that in three dimensions the tearing instability produces a network of interconnected and interacting magnetic flux ropes. In its nonlinear evolution, the current sheet evolves toward a three-dimensional, disordered state in which the resulting flux rope segments contain magnetic substructure on kinetic scales and sites of temporally and spatially intermittent dissipation. We find that reconnection produces significant particle acceleration, primarily due to the electric field in the X-line regions between flux ropes; the resulting particle energy spectrum can extend to high Lorentz factors. We find that the highest energy particles are moderately beamed within.en
dc.description.departmentAstronomyen
dc.format.mimetypeapplication/pdfen
dc.identifier.urihttp://hdl.handle.net/2152/25894en
dc.subjectAstrophysicsen
dc.subjectPlasma physicsen
dc.titleMagnetic instabilities and resulting energy conversion in astrophysicsen
dc.typeThesisen
thesis.degree.departmentAstronomyen
thesis.degree.disciplineAstronomyen
thesis.degree.grantorThe University of Texas at Austinen
thesis.degree.levelDoctoralen
thesis.degree.nameDoctor of Philosophyen
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